Wednesday, April 8, 2015
PSA test for prostate cancer screening does more harm than good
Some doctors are better than others. And some are pathetically behind the curve. Why did the doctor I visited order a PSA test given that 1. I'm asymptomatic and 2. PSA screening has been shown to do more harm than good?
We know that the sensitivity and specifities of screening tests are imperfect. We also know the prevalence of the diseases they're trying to detect tends to be low. Hence, screening tests have high false discovery rates (the ratio of false positives to total positives). We also know the perils of overdiagnosis and overtreatment--detecting and treating abnormalities/cancers that will never be the cause of death of the individual. Therefore the rationale for ordering some screening (as opposed to diagnostic) tests is dodgy at best.